Additive Combination of Spectra Reflected from Porous Silicon and Carbon/Porous Silicon Rugate Filters to Improve...

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Optical vapor sensing using porous silicon photonic crystals faces selectivity challenges.
• Existing methods struggle to differentiate between various vapor analytes accurately.

Purpose of the Study:

• To develop a method for improving the optical vapor selectivity of porous silicon rugate filters.
• To investigate the additive spectral analysis of functionalized surfaces for enhanced sensing.

Main Methods:

• Fabrication of two porous silicon rugate filter substrates with distinct surface functionalities: oxidized and carbonized.
• Analysis of reflected light spectra from individual and combined substrates exposed to vapor analytes.
• Comparison of peak shift trends to assess vapor affinities and selectivity.

Main Results:

• Individual substrates showed sensitivity but lacked selectivity towards vapor analytes.
• Additive spectral analysis of the two substrates significantly improved selectivity.
• Enhanced selectivity was observed even at low vapor pressures and for analytes with similar properties.

Conclusions:

• Combining spectral data from functionalized porous silicon surfaces offers a viable strategy to enhance optical vapor sensor selectivity.
• This additive spectral approach holds promise for developing more robust and selective one-dimensional photonic crystal-based sensors.